Hopefully such shameless self-promotion as this isn't frowned upon here, but I recently wrote a shell script to implement effective dynamic DNS for Gandi.net domain names. I have a dynamic IP address at home and was getting a bit frustrated with it, so I threw this together one weekend. There are Python, etc. XML-RPC libraries available but I guess I'm a bit masochistic so I did this in the shell. Hopefully it can help someone else who uses Gandi for DNS.